The present invention relates to measuring relative fractions of liquid (nonconductive) and vapor, or solids (nonconductive) and gases; such as occurs in fuel or oil pumping or pneumatic conveying of solid particles.
The prior art includes a number of mechanical and electrical approaches to the problem limited principally in their failure to deal effectively with the non-homogeneous character of the vapor and liquid or solid and gas mixture across the cross section of a conduit in most practical applications. See also the following references:
1. LeTourneau, B. W., and Bergles, A. E., Co-Chairmen of a Symposium on "Two-Phase Flow Instrumentation," 11th National ASME/AIChE Heat Transfer Conference, Minneapolis, Minn. 1969. PA0 2. Hewitt, G. F., "The Role of Experiments in Two-Phase Systems with Particular Reference to Measurement Techniques," Progress in Heat and Mass Transfer, Vol. 6, 1972, p. 295. PA0 3. Subbotin, V. I., Pakhvalov, Yu. E., Mikhailov, L. E., Leonov, V. A., and Kronin, I. V., "Resistance and Capacitance Methods of Measuring Steam Contents," Teploenergetika, Vol. 21, No. 6, 1974, p. 63. PA0 4. Olsen, H. O., "Theoretical and Experimental Investigation of Impedance Void Meters," Kjeller report KR-118, 1967. PA0 5. orbeck, I., "Impedance Void Meter," Kjeller report KR-32, 1962. PA0 6. maxwell, J. C., "A Treatise on Electricity and Magnetism," Clarendon Press, Oxford, 1881. PA0 7. Bruggeman, D. A. G., "Berechnung Verschiedener Physikalischer Konstanten von Heterogenen Substanzen," Ann. Phys., Leipzig, Vol. 24, 1935, p. 636. PA0 8. Hewitt, G. F., and Hall-Taylor, N. S., "Annular Two-Phase Flow," Pergamon Press, 1970, p. 153. PA0 9. Jones, O. C., Jr., and Zuber, N., "The Interrelation Between Void Fraction Fluctuations and Flow Patterns in Two-Phase Flow," Int. J. Multiphase Flow, Vol. 2, 1975, p. 273,
as well as our prior U.S. applications stated above. In particular, the latter discloses a measured conductivity variation to determination of mixed flow conditions and is embodied in the commercially available Auburn International Inc. model 1080 and 1075 instruments.
It is an important object of the invention to provide vapor and liquid fraction of nonconductive gas and solids fraction measurement in a mixed flow dealing effectively with the non-homogeneous cross section profile of such mixtures.
It is a further object of the invention to achieve the measurement over a relatively short length of conduit and not be adversely affected by the spiraling effect of annular flow.
It is a further object of the invention to provide a long lived apparatus dealing with environmental conditions such as thermal expansion and contraction and pressure in an effective way providing long reliable life operation consistent with one or more of the preceding objects.
It is a further object of the invention to provide a simple construction making a minimal disturbance on the system being measured consistent with one or more of the preceding objects.
It is a further object of the invention to screen out sources of spurious readings consistent with one or more of the preceding objects.
It is a further object of the invention to provide an economical device consistent with one or more of the preceding objects.